There is a great need for methods and devices that can perform cooling and heating on a very rapid (subsecond) time scale. Such rapid thermocycling techniques would find applications in polymerase chain reaction (PCR) techniques for fast amplification of genetic materials. Current PCR devices and methods require several hours to obtain enough amplified genetic materials for further analysis. In times of terrorist threats, possible attacks with weapons of mass destruction (WMD), or in a case of any disaster, there is need for rapid medical responses in a variety of scenarios, where biochemical information is often required within minutes or even seconds.
The heating of objects can be performed very quickly by electromagnetic radiation and other thermal means. However, cooling objects to ambient temperature or below ambient temperature requires more time. Common cooling sources used for cooling objects are thermoelectrical devices based on the Peltier effect. These devices are not energy-efficient and cooling of objects is often much slower than required.
Another great need, particularly useful in the PCR technique, is non-contact heating and/or non-contact cooling. Non-contact heating of objects can be performed relatively easily and fast by various means including electromagnetic radiation, but means for very efficient non-contact cooling of objects do not exist. The pressure air-cooling technique is currently one of the solutions for non-contact cooling, but in use this technique is neither fast nor convenient enough.
Another great need for fast cooling and heating exists in therapeutic devices, such as acupuncture devices or other therapeutic devices that through bioactive treat the body. Nerve reactions and many other physiological processes occur on subsecond scale and therapeutic devices with thermocycling rates within this time scale would have great therapeutic value. Sports medicine also would greatly benefit from cooling-heating devices, which can be worn over the injured site to shorten the time of healing.
New techniques are also needed for cooling the backs of high-performance integrated circuits (ICs), which could allow for denser packaging of chips, while providing better temperature control and improved reliability. As the power density of high-performance integrated circuits increases, cooling of integrated circuits has become more significant concern. Conventional cooling techniques, which depend on heat sinks on the backs of ICs to transfer heat into streams of forced air, will be unable to meet the needs of future power-hungry devices—especially 3D multi-chip modules that will pack more processing power into less space.